Techniques for providing a replacement valve and transseptal communication

ABSTRACT

A method is provided, including (1) identifying the subject as having mitral valve regurgitation; (2) during a medical procedure, in response to identifying the subject as having mitral valve regurgitation, implanting a prosthetic valve at a mitral valve site of the heart; and (3) during the same medical procedure, implanting a therapeutic septal device at a septum of the heart. Other embodiments are also described.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. Ser. No. 15/433,547 toHariton et al., filed Feb. 15, 2017, and entitled “Techniques forproviding a replacement valve and transseptal communication,” which isnow U.S. Pat. No. 10,531,866, and which claims the benefit of U.S.Provisional application 62/295,701 to Hariton et al., filed Feb. 16,2016, and entitled “Techniques for providing a replacement valve andtransseptal communication.” Each of the above is incorporated herein byreference.

FIELD OF THE INVENTION

Some applications of the present invention relate in general to cardiacimplants. More specifically, some applications of the present inventionrelate to techniques for implanting cardiac implants in a complementarymanner.

BACKGROUND

Ischemic heart disease causes regurgitation of a heart valve by thecombination of ischemic dysfunction of the papillary muscles, and thedilatation of the ventricle that is present in ischemic heart disease,with the subsequent displacement of the papillary muscles and thedilatation of the valve annulus.

Dilation of the annulus of the valve prevents the valve leaflets fromfully coapting when the valve is closed. Regurgitation of blood from theventricle into the atrium results in increased total stroke volume anddecreased cardiac output, and ultimate weakening of the ventriclesecondary to a volume overload and a pressure overload of the atrium.

SUMMARY OF THE INVENTION

For some applications, during a single medical procedure, a prostheticvalve is implanted in the heart of a subject, and a transseptalfenestration is made in the heart. For example, the implantation andfenestration may be performed via the same transapical access point(i.e., made by transapical puncture). Alternatively, the implantation orthe fenestration may be performed via the transapical access point, andthe other may be performed via transfemoral access. Typically, theprocedure is performed on a subject that has been identified as havingmitral valve regurgitation.

For some applications, the transseptal fenestration is made in theinteratrial septum of the heart. For some applications, the transseptalfenestration is made in the interventricular septum of the heart.

For some applications, the transseptal fenestration is left as-is, as atransseptal shunt. For some applications, a septal device is implantedat (e.g., in) the transseptal fenestration. For some applications, theseptal device is a shunt device, which is implanted at the fenestrationso as to maintain patency. For some applications, the septal device is aflow-restricting device, such as a valve or a membrane, which isimplanted at the fenestration so as to allow limited flow of bloodbetween the right and left sides of the heart. For example, flow may beallowed in only one direction, and/or in response to a blood pressuredifference that is greater than a threshold blood pressure difference.

For some applications, the septal device comprises a membrane or aballoon, and is implanted at the fenestration so as to facilitatetemporary and reversible changes in the effective volume of the leftatrium or left ventricle of the heart, e.g., without allowing mixing ofblood between the right and left sides of the heart. For someapplications, the septal device comprises a cell that performs a similarfunction. For example, the cell may slide into and out of the right sideof the heart (e.g., the right atrium) in response to the blood pressuredifference.

For some applications, the membrane, balloon, and/or cell is implantedin the heart wall, rather than in the septum.

There is therefore provided, in accordance with an application of thepresent invention, a method for use with a heart of a subject, themethod including:

making a transapical puncture into a left ventricle of the heart;

making a transseptal fenestration in the heart;

delivering a prosthetic valve via the transapical puncture andimplanting the prosthetic valve at a mitral valve of the heart; and

subsequently to delivering the prosthetic valve and making thetransseptal fenestration, closing the transapical puncture.

In an application, the subject has not been identified as suffering fromheart failure, and performing the method includes performing the methodon the subject that has not been identified as suffering from heartfailure.

In an application, making the transseptal fenestration includes makingthe transseptal fenestration via the transapical puncture.

In an application, making the transseptal fenestration includes makingthe transseptal fenestration via a transfemoral route.

In an application, making the transseptal fenestration includes making afenestration in the interventricular septum.

In an application, making the transseptal fenestration includes making afenestration in the interatrial septum.

In an application, making the transseptal fenestration includes makingthe transseptal fenestration after implanting the prosthetic valve.

In an application, making the transseptal fenestration includes makingthe transseptal fenestration before implanting the prosthetic valve.

In an application, the method further includes advancing a distal end ofa tube through the transapical puncture, and delivering the prostheticvalve via the transapical puncture includes delivering the prostheticvalve via the tube.

In an application, making the transseptal fenestration includes makingthe transseptal fenestration via the tube.

In an application, the method further includes implanting a shunt deviceinto the transseptal fenestration.

In an application, the shunt device includes a check valve, andimplanting the shunt device includes implanting the shunt device suchthat the check valve facilitates one-way blood flow from a chamber ofthe left side of the heart, via the transseptal fenestration, to achamber of the right side of the heart.

In an application, implanting the shunt device includes implanting ashunt device that is shaped to define a lumen, and includes a membranethat regulates blood flow through the lumen.

In an application, implanting the shunt device includes implanting ashunt device that includes a membrane that (a) has (i) a closed positionin which the membrane inhibits blood flow through the lumen, and (ii) anopen position in which the inhibiting of the blood flow is reduced,resides in the closed position while a blood pressure difference acrossthe membrane is lower than a threshold blood pressure difference of 4-6mmHg (e.g., 5 mmHg), and moves from the closed position into the openposition in response to the blood pressure difference exceeding thethreshold blood pressure difference.

In an application, the membrane moves from the closed position into theopen position in response to the blood pressure difference exceeding thethreshold blood pressure difference in either direction across themembrane, and implanting the shunt device that includes the membraneincludes implanting the shunt device that includes the membrane thatmoves from the closed position into the open position in response to theblood pressure difference exceeding the threshold blood pressuredifference in either direction across the membrane.

In an application, the membrane is transected by intersecting slits, andimplanting the shunt device includes implanting the shunt device thatincludes the membrane that is transected by intersecting slits.

In an application, the method further includes implanting at thetransseptal fenestration, a balloon device that includes a balloonhaving an interior and an opening into the interior, such that (i) theinterior is in fluid communication, via the opening, with a chamber ofthe left side of the heart, and (ii) a greater blood pressure in thechamber of the left side of the heart relative to a blood pressure in acorresponding chamber of the right side of the heart inflates theballoon such that the balloon reversibly expands into the correspondingchamber of the right side of the heart.

In an application, the balloon is elastic, and implanting the balloondevice includes implanting the balloon device such that the balloonautomatically deflates in response to a reduction in the greater bloodpressure in the chamber of the left side of the heart.

In an application, implanting the balloon device includes implanting theballoon such that the balloon inflates only when blood pressure in thechamber of the left side of the heart is more than 4-6 mmHg greater thanblood pressure in the chamber of the right side of the heart.

In an application, implanting the balloon device includes sealing thetransseptal fenestration with the balloon device.

In an application, the method further includes implanting at thetransseptal fenestration, an elastic membrane that elastically expandsin response to a difference in blood pressure across the membrane.

In an application, implanting the elastic membrane includes sealing thetransseptal fenestration with the elastic membrane.

In an application, the method further includes implanting at thetransseptal fenestration, a cell having an interior and an opening intothe interior, such that (i) the interior is in fluid communication, viathe opening, with a chamber of the left side of the heart, and (ii) agreater blood pressure in the chamber of the left side of the heartrelative to a blood pressure in a corresponding chamber of the rightside of the heart increases a volume of the interior that is disposedwithin the corresponding chamber of the right side of the heart.

In an application, the cell includes an elastic membrane, and implantingthe cell includes implanting the cell that includes the elasticmembrane, such that the elastic membrane elastically expands into thechamber of the right side of the heart in response to the greater bloodpressure in the chamber of the left side of the heart.

In an application, the cell is a balloon, and implanting the cellincludes implanting the balloon, such that the balloon expands into thechamber of the right side of the heart in response to the greater bloodpressure in the chamber of the left side of the heart.

In an application, implanting the cell includes implanting a cell thatis slidably mounted in a mount, such that the mount is fixed at thetransseptal fenestration, and the cell slides into the chamber of theright side of the heart in response to the greater blood pressure in thechamber of the left side of the heart.

In an application, implanting the cell includes implanting the cell suchthat the volume of the interior that is disposed within thecorresponding chamber of the right side of the heart increases only whenthe blood pressure in the chamber of the left side of the heart isgreater than the blood pressure in the chamber of the right side of theheart by more than a threshold difference of 4-6 mmHg.

There is further provided, in accordance with an application of thepresent invention, a method including for use with a heart of a subject:

identifying the subject as having mitral valve regurgitation;

during a medical procedure, in response to identifying the subject ashaving mitral valve regurgitation, implanting a prosthetic valve at amitral valve site of the heart; and

during the same medical procedure, implanting a shunt device at a septumof the heart.

In an application, implanting the prosthetic valve and implanting theshunt device include implanting the prosthetic valve and implanting theshunt device in the absence of an identification of the subject ashaving heart failure.

In an application, the septum is an interatrial septum of the heart, andimplanting the shunt device at the septum includes implanting the shuntdevice at the interatrial septum.

In an application, the septum is an interventricular septum of theheart, and implanting the shunt device at the septum includes implantingthe shunt device at the interventricular septum.

In an application, the subject is an adult subject, and the method isperformed on the adult subject.

There is further provided, in accordance with an application of thepresent invention, a method including for use with a heart of a subject:

identifying the subject as having mitral valve regurgitation;

during a medical procedure, in response to identifying the subject ashaving mitral valve regurgitation, implanting a prosthetic valve at amitral valve site of the heart; and

during the same medical procedure, implanting a septal device at aseptum of the heart.

In an application, implanting the prosthetic valve and implanting theseptal device include implanting the prosthetic valve and implanting theseptal device in the absence of an identification of the subject ashaving heart failure.

In an application, the septum is an interatrial septum of the heart, andimplanting the septal device at the septum includes implanting theseptal device at the interatrial septum.

In an application, the septum is an interventricular septum of theheart, and implanting the septal device at the septum includesimplanting the septal device at the interventricular septum.

In an application, the subject is an adult subject, and the method isperformed on the adult subject.

The present invention will be more fully understood from the followingdetailed description of applications thereof, taken together with thedrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-F are schematic illustrations of a method for use with a heartof a subject, in accordance with some applications of the invention;

FIGS. 2A-F are schematic illustrations of a method for use with heart ofa subject, in accordance with some applications of the invention;

FIGS. 3A-B are schematic illustrations of a method for use with heart ofa subject, in accordance with some applications of the invention;

FIGS. 4, 5, 6, 7 and 8 are schematic illustrations of respective septaldevices that may be implanted at the transseptal fenestration, inaccordance with some applications of the invention; and

FIGS. 9 and 10 are schematic illustrations of septal devices implantedin the heart wall, in accordance with an application of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference is made to FIGS. 1A-F, which are schematic illustrations of amethod for use with a heart 20 of a subject, in accordance with someapplications of the invention. Heart 20 has a left atrium 22 and a leftventricle 24 (the left side of the heart), and a right atrium 26 and aright ventricle 28 (the right side of the heart).

A transapical puncture is made into left ventricle 24 (FIG. 1A). Forsome applications, a tube 40 is introduced through the transapicalpuncture. Via the transapical puncture (e.g., via tube 40), atransseptal fenestration is made in interatrial septum 30 (e.g., in thefossa ovalis) (FIG. 1B). For some applications, a septal device 42(e.g., a shunt device) is implanted at the transseptal fenestration(FIG. 1C). Subsequently, via the transapical puncture (e.g., via tube40), a prosthetic valve 44 is delivered (FIG. 1D) and implanted atmitral valve 32 of the subject (FIG. 1E). Subsequently, the transapicalpuncture is closed (FIG. 1F).

Reference is made to FIGS. 2A-F, which are schematic illustrations of amethod for use with heart 20 of a subject, in accordance with someapplications of the invention. The method of FIGS. 2A-F is similar tothat of FIGS. 1A-F, except that (i) prosthetic valve 44 is delivered andimplanted prior to making the transseptal fenestration (FIGS. 2B-C), and(ii) the transseptal fenestration is made (and optionally a septaldevice 52, such as a shunt device, is implanted) in interventricularseptum 34 (FIGS. D-E).

Reference is again made to FIGS. 1A-2F. It is to be noted that the scopeof the invention includes making the transseptal fenestration ininterventricular septum 34 even when making the transseptal fenestrationprior to implantation of prosthetic valve 44. It is also to be notedthat the scope of the invention includes implanting prosthetic valve 44prior to making the transseptal fenestration even for applications inwhich the transseptal fenestration is made in the interatrial septum.

Reference is made to FIGS. 3A-B, which are schematic illustrations of amethod for use with heart 20 of a subject, in accordance with someapplications of the invention. The method shown in FIGS. 3A-B isidentical to those described with reference to FIGS. 1A-2F hereinabove,except that the transseptal fenestration is made (and optionally, septaldevice 42 or 52 is implanted) via a transvenous (e.g., transfemoral)route. The transseptal fenestration (and/or the implantation of septaldevice 42 or 52) may be made before or after prosthetic valve 44 isimplanted. FIGS. 3A-B show the transseptal fenestration in interatrialseptum 30, but it is to be noted that the scope of the inventionincludes the transseptal fenestration being in interventricular septum34, mutatis mutandis).

Reference is again made to FIGS. 1A-3B. For some applications, ratherthan via transapical puncture, prosthetic valve 44 is implanted via atransatrial puncture (i.e., a puncture through the heart wall intoatrium 22). For such applications, the transseptal fenestration may bemade via the transatrial puncture or via a different route.

Reference is again made to FIGS. 1A-3B. It is to be noted thatprosthetic valve 44 is not delivered to mitral valve 32 via thetransseptal fenestration. That is, the transseptal fenestrationdescribed herein is not itself required for delivery of the prostheticvalve.

Reference is now made to FIGS. 4-8, which are schematic illustrations ofseptal devices that may be implanted at the transseptal fenestration, inaccordance with some applications of the invention. Hereinabove a shuntdevice is used as an example of devices 42 and 52. A shunt device istypically used to maintain patency of the transseptal fenestration. Forexample, and as shown in FIG. 2C, a shunt device may have a tubularportion 54 that is shaped to define a lumen, with flanges 56 (that aretypically expandable) that engage the tissue of the septum, and retainthe shunt device within the transseptal fenestration. FIGS. 4-8 areother examples of devices that may be implanted in place of device 42 ordevice 52, mutatis mutandis.

FIG. 4 is a schematic illustration of a septal device 60 that is shapedto define a lumen, and comprises a check valve 62 that facilitatesone-way blood flow through the lumen (and thereby through thetransseptal fenestration). Device 60 is typically oriented such that theone-way blood flow is from a chamber of the left side of the heart to achamber of the right side of the heart (e.g., from left atrium 22 toright atrium 26, or from left ventricle 24 to right ventricle 28). Checkvalve 62 is shown as a leaflet or duckbill valve, but it is to beunderstood that any suitable check valve known in the art may be used(such as, but not limited to, a ball-and-cage valve or a tilting-discvalve). For some applications (e.g., when check valve 62 is a leaflet orduckbill valve), check valve 62 thereby comprises a membrane (i.e., theleaflets or the duckbill membrane) that regulates blood flow through thelumen of the valve.

Frame A shows a state of device 60 (i.e., closed) when a blood pressuredifference across the device (e.g., across valve 62) is less than athreshold blood pressure difference. That is, when blood pressure on theleft side of the heart is less than a threshold amount greater thanblood pressure on the right side of the heart (e.g., including if thepressure on the left side of the heart is not greater than the pressureon the right side of the heart). Frame B shows a state of device 60(i.e., open) when the blood pressure difference is greater than thethreshold blood pressure difference. For some applications, thethreshold blood pressure difference for device 60 is 4-6 mmHg (e.g., 5mmHg).

FIG. 5 is a schematic illustration of a septal device 70 that comprisesa membrane 72 that regulates blood flow through the lumen. Device 70 isthereby similar to device 60. In contrast to device 60, membrane 72regulates blood flow but in a bidirectional manner. Membrane 72 opensbidirectionally in response to a blood pressure difference that isgreater than a threshold blood pressure difference in either direction.Frame A shows a state of device 70 when blood pressure on the left sideof the heart is more than the threshold difference greater than pressureon the right side of the heart. Frame C shows the opposite state. FrameB shows a state of device 70 (i.e., closed, thereby inhibiting bloodflow through the lumen of the device) when the blood pressure differenceacross the device (e.g., across membrane 72) is less than the thresholdblood pressure difference. For some applications, the threshold bloodpressure difference for device 70 is 4-6 mmHg (e.g., 5 mmHg) (in eitherdirection).

For some applications, membrane 72 is transected by intersecting slits74, which form the membrane into flaps, which flap open and closed asshown.

FIGS. 6 and 7 show septal devices 80 and 90, respectively, which alsoeach comprise a membrane. However, the membranes of these devices do notfacilitate blood flow between the left and right sides of the heart.Rather, implantation of these devices seals the transseptal fenestrationwith the membrane.

Device 80 comprises a membrane 82, and device 90 comprises a membrane92. Membranes 82 and 92 are similar, are both elastic, and bothelastically expand (i.e., stretch) in response to a difference in bloodpressure across the membrane. Membrane 92 may be considered to be aballoon (e.g., having an interior 94 even in the absence of a pressuredifference across the membrane), whereas membrane 82 is generally planarin the absence of a pressure difference across the membrane. Device 90has an opening 96 into interior 94, and is implanted such that theinterior is in fluid communication, via the opening, with the chamber ofthe left side of the heart. For both FIG. 6 and FIG. 7, frame A shows astate of the device in the absence of a pressure difference across themembrane, frame B shows a state of the device in the presence of apressure difference across the membrane, and frame C shows a state ofthe device in the presence of a larger pressure difference across themembrane.

By elastically expanding, membranes 82 and 92 increase the effectivevolume of the chamber of the left side of the heart, thereby reducingthe blood pressure in that chamber without mixing of blood between theleft and right sides of the heart.

It is alternatively possible to describe the balloon of device 90, asbeing a cell that has an interior 94 and an opening 96 into theinterior. Device 90 is implanted such that (i) the interior is in fluidcommunication, via the opening, with a chamber of the left side of theheart, and (ii) a greater blood pressure in the chamber of the left sideof the heart relative to a blood pressure in a corresponding chamber ofthe right side of the heart increases a volume of interior 94 that isdisposed within the corresponding chamber of the right side of theheart. This occurs by membrane 92 elastically expanding into the chamberof the right side of the heart in response to this pressure difference.

For some applications, membrane 82 and/or membrane 92 inflate only whenblood pressure in the chamber of the left side of the heart is more than4-6 mmHg (e.g., 5 mmHg) greater than blood pressure in the chamber ofthe right side of the heart.

The membrane/balloon of devices 80 and 90 may be biased to automaticallycontract/deflate in response to a reduction of the difference in bloodpressure across the fenestration, even if the blood pressure in thechamber of the right side of the heart does not exceed that of thechamber of the left side of the heart.

FIG. 8 shows a septal device 100 that comprises a cell 102 that isslidably mounted in a mount 108, such that the mount is fixed at thetransseptal fenestration, and the cell slides into the chamber of theright side of the heart in response to the greater blood pressure in thechamber of the left side of the heart. Cell 102 has an interior 104 andan opening 106 into the interior, and is implanted such that theinterior is in fluid communication, via the opening, with the chamber ofthe left side of the heart. Frame A shows the cell not protruding (orprotruding minimally) into the chamber of the right side of the heart,and frame B shows the cell having slid into the chamber of the rightside of the heart. For some applications, cell 102 is biased (e.g.,spring-loaded) to automatically slide out of the chamber of the rightside of the heart in response to a reduction of the difference in bloodpressure across the fenestration, even if the blood pressure in thechamber of the right side of the heart does not exceed that of thechamber of the left side of the heart.

For some applications, cell 102 slides into the chamber of the rightside of the heart only when blood pressure in the chamber of the leftside of the heart is more than 4-6 mmHg (e.g., 5 mmHg) greater thanblood pressure in the chamber of the right side of the heart.

It is hypothesized by the inventors that the implantation of a septaldevice described hereinabove in addition to the implantation ofprosthetic valve 44 improves a likelihood of a successful long-termoutcome of the procedure. For example, the septal devices may facilitatereduction of elevated blood pressure in the right side of the heart,should regurgitation through or around prosthetic valve 44 begin tooccur subsequently to implantation of the prosthetic valve. Thereforethe implantation of such a septal device may be considered to beprophylactic. For some applications of the invention, the methodsdescribed hereinabove are performed on a subject (e.g., an adultsubject) who does not suffer from and/or has not been identified (e.g.,diagnosed) as suffering from heart failure.

Therefore, a method according to some applications of the inventioncomprises: (i) making a transseptal fenestration in a heart of a subject(e.g., an adult subject) who has not been identified as suffering fromheart failure; (2) advancing a shunt device into the heart; and (3)implanting the shunt device at the transseptal fenestration. Similarly,another method according to some applications of the inventioncomprises: (1) identifying an adult subject as not suffering from heartfailure; and (2) subsequently, making a transseptal fenestration in aheart of the subject.

Reference is now made to FIGS. 9 and 10, which are schematicillustrations of a device 110 and a device 120 implanted in the heartwall, in accordance with an application of the invention. For someapplications, devices that reversibly increase the effective volume ofthe chamber of the left side of the heart are implanted in the heartwall, rather than (as described hereinabove for devices 80, 90 and 100)at a transseptal fenestration. FIG. 9 shows device 110 implanted in thewall of left atrium 22, and FIG. 10 shows device 120 implanted in thewall of left ventricle 24. Devices 110 and 120 may be similar instructure and function (if not dimension) to devices 80, 90 or 100,mutatis mutandis.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove, as well as variations and modifications thereofthat are not in the prior art, which would occur to persons skilled inthe art upon reading the foregoing description.

The invention claimed is:
 1. A method for use with a heart of a subject,comprising: identifying the subject as having mitral valveregurgitation; during a medical procedure, in response to identifyingthe subject as having mitral valve regurgitation, implanting aprosthetic valve at a mitral valve site of the heart; and during thesame medical procedure, implanting a shunt including a check valve at aseptum of the heart such that the check valve facilitates one-way bloodflow from a chamber of a left side of the heart, via the shunt, to achamber of a right side of the heart.
 2. The method according to claim1, wherein implanting the prosthetic valve and implanting the shuntrespectively comprise implanting the prosthetic valve and implanting theshunt in an absence of an identification of the subject as having heartfailure.
 3. The method according to claim 1, wherein the septum is aninteratrial septum of the heart, and wherein implanting the shunt at theseptum comprises implanting the shunt at the interatrial septum.
 4. Themethod according to claim 1, wherein the septum is an interventricularseptum of the heart, and wherein implanting the shunt at the septumcomprises implanting the shunt at the interventricular septum.
 5. Themethod according to claim 1, wherein the subject is an adult subject,and wherein the method is performed on the adult subject.
 6. The methodaccording to claim 1, further comprising making a fenestration in theseptum of the heart, and delivering the prosthetic valve transfemorallyto the heart and through the fenestration to the mitral valve site, andwherein implanting the shunt comprises implanting the shunt in thefenestration.
 7. The method according to claim 6, further comprisingtransfemorally delivering the shunt to the septum.
 8. The methodaccording to claim 6, wherein making the fenestration comprises makingthe fenestration transfemorally.
 9. The method according to claim 1,further comprising transapically making a fenestration in the septum ofthe heart, wherein implanting the shunt comprises implanting the shuntin the fenestration.
 10. The method according to claim 1, furthercomprising transapically delivering the prosthetic valve to the mitralvalve site.
 11. The method according to claim 1, wherein implanting theshunt comprises implanting the shunt after implanting the prostheticvalve.
 12. The method according to claim 1, wherein implanting the shuntcomprises implanting the shunt before implanting the prosthetic valve.13. A method for use with a heart of a subject, comprising: identifyingthe subject as having mitral valve regurgitation; during a medicalprocedure, in response to identifying the subject as having mitral valveregurgitation, implanting a prosthetic valve at a mitral valve site ofthe heart; and during the same medical procedure, implanting a shunt ata septum of the heart, the shunt being shaped to define a lumen andincluding a membrane that regulates blood flow through the lumen,wherein: the membrane: has a closed position in which the membraneinhibits blood flow through the lumen, and an open position in which theinhibiting of the blood flow by the membrane is reduced, resides in theclosed position while a blood pressure difference across the membrane islower than a threshold blood pressure difference, moves from the closedposition into the open position in response to the blood pressuredifference exceeding the threshold blood pressure difference, and isconfigured such that the threshold blood pressure difference is 4-6mmHg, and implanting the shunt that is shaped to define the lumen andincludes the membrane comprises implanting the shunt that is shaped todefine the lumen and includes the membrane that: has the closed positionand the open position, resides in the closed position while the bloodpressure difference across the membrane is lower than the thresholdblood pressure difference, moves from the closed position into the openposition in response to the blood pressure difference exceeding thethreshold blood pressure difference, and is configured such that thethreshold blood pressure difference is 4-6 mmHg.
 14. The methodaccording to claim 13, wherein the membrane is configured to move fromthe closed position into the open position in response to the bloodpressure difference exceeding the threshold blood pressure difference ineither direction across the membrane, and wherein implanting the shuntthat includes the membrane comprises implanting the shunt that includesthe membrane that is configured to move from the closed position intothe open position in response to the blood pressure difference exceedingthe threshold blood pressure difference in either direction across themembrane.
 15. The method according to claim 13, wherein the membrane istransected by intersecting slits, and wherein implanting the shuntcomprises implanting the shunt that includes the membrane that istransected by intersecting slits.
 16. The method according to claim 13,wherein implanting the prosthetic valve and implanting the shuntrespectively comprise implanting the prosthetic valve and implanting theshunt in an absence of an identification of the subject as having heartfailure.
 17. The method according to claim 13, wherein the septum is aninteratrial septum of the heart, and wherein implanting the shunt at theseptum comprises implanting the shunt at the interatrial septum.
 18. Themethod according to claim 13, wherein the septum is an interventricularseptum of the heart, and wherein implanting the shunt at the septumcomprises implanting the shunt at the interventricular septum.
 19. Themethod according to claim 13, wherein the subject is an adult subject,and wherein the method is performed on the adult subject.
 20. The methodaccording to claim 13, further comprising making a fenestration in theseptum of the heart, and delivering the prosthetic valve transfemorallyto the heart and through the fenestration to the mitral valve site, andwherein implanting the shunt comprises implanting the shunt in thefenestration.
 21. The method according to claim 20, further comprisingtransfemorally delivering the shunt to the septum.
 22. The methodaccording to claim 20, wherein making the fenestration comprises makingthe fenestration transfemorally.
 23. The method according to claim 13,further comprising transapically making a fenestration in the septum ofthe heart, wherein implanting the shunt comprises implanting the shuntin the fenestration.
 24. The method according to claim 13, furthercomprising transapically delivering the prosthetic valve to the mitralvalve site.
 25. The method according to claim 13, wherein implanting theshunt comprises implanting the shunt after implanting the prostheticvalve.
 26. The method according to claim 13, wherein implanting theshunt comprises implanting the shunt before implanting the prostheticvalve.